1. Technical Field
The present invention relates to a tape cartridge installed on the cartridge installation portion of a tape printing apparatus to be used and, in particular, to a tape cartridge on which a printing tape and an ink ribbon are mounted.
2. Background Art
As such a tape cartridge and a tape printing apparatus using the tape cartridge, the following tape cartridge and tape printing apparatus have been known (see JP-A-2012-20543).
The tape cartridge includes a tape body in which a printing tape is wound on a tape core, a ribbon body in which an ink ribbon is wound on a ribbon winding-up core, a ribbon winding-up core that winds up the ink ribbon that has been consumed, a platen roller that feeds out and supplies the printing tape from the tape body, and a cartridge casing in which the tape body, the ribbon body, the ribbon winding-up core, and the platen roller are accommodated.
On the other hand, on the bottom plate of the cartridge installation portion of the tape printing apparatus, a positioning projection that positions the tape core, a printing head covered with a head cover, a platen driving shaft that rotates the platen roller, and a ribbon winding-up driving shaft that winds up the ink ribbon via the ribbon winding-up core are provided. In addition, in the lower side space of the cartridge installation portion, a motor-driven tape feeding mechanism that rotates the platen driving shaft and the ribbon winding-up driving shaft is embedded.
Meanwhile, when the tape cartridge is installed on such a cartridge installation portion, the head cover naturally functions as an initial installation guide. While, if the head cover is provided with a rib for reinforcing the head cover, it is required to increase the insertion opening of the tape cartridge so as to correspond to the size of the projecting rib without spoiling the guiding function. However, the increase in the opening projection causes the gap between the head cover and the insertion opening, whereby dust or the like may easily intrude into the vicinity of the printing head or the platen roller.
In such a known tape cartridge, a rotation force is applied from the platen driving shaft to the platen roller to feed the printing tape and the ink ribbon when the tape cartridge is installed on the cartridge installation portion. Similarly, a rotation force is applied from the ribbon winding-up driving shaft to the ribbon winding-up core to wind up the ink ribbon. Some of the rotation force input to the platen roller is applied as a rotation moment to the cartridge casing via a bearing portion by the friction between the platen roller and the bearing portion. Similarly, some of the rotation force input to the ribbon winding-up core is also applied to the cartridge casing as a rotation moment.
In this case, the platen roller rotates clockwise when seen in plan view, and the ribbon winding-up core rotates counterclockwise when seen in plan view. Thus, the resultant force of the rotation moment on the side of the platen roller and the rotation moment on the side of the ribbon winding-up core is applied to the tape cartridge. Since the rotation forces have no vector components that cancel each other on an imaginary line connecting the platen roller and the ribbon winding-up core together, they are overlapped with each other in a direction crossing the imaginary line, whereby the resultant force is applied as the largest force. For this reason, there is a likelihood that the position of the tape cartridge is deviated inside the cartridge installation portion when the tape printing apparatus is driven to perform printing. Further, the positional deviation of the tape cartridge results in the positional deviation of the tape cartridge with respect to the printing head, which gives an adverse affect on printing quality.
The present invention has an object of providing a tape cartridge that can reduce the intrusion of dust without spoiling an installation guiding function with respect to a cartridge installation portion and prevent its positional deviation inside a cartridge installation portion.